The purpose of the research training plan is 1) to provide a sound theoretical foundation in the design and analysis of periodontal clinical trials and 2) to carry out a population bases case-control study investigating the genetic epidemiology of early onset periodontitis. This goal will be achieved by a structured 5-t=year program intended to provide exposure to epidemiological and biostatistical methodology leading to a PhD degree in Epidemiology. The training in Phase-I will consist of 5 components: (1) Course work in epidemiology, statistics, and biostatistics; (2) Independent study in the area of correlated data analysis; (3) Methodological research on extending existing statistical and epidemiological methods to problems of design and analysis of clinical studies of periodontal disease; (4) Meta-analysis of published studies on treatment efficacy for periodontal diseases; and (5) Participation in teaching an introductory biostatistics course in dental graduate students. The criteria for proceeding to Phase II of he programs are: (a) Satisfactory completion of courses outlined in Parts (1) and (2) of Phase I; (b) completion of an article or monograph to be submitted for publication addressing the methodologic issues in clinical studies of periodontal diseases; (c) completion of an article to be submitted for publication addressing the meta-analysis conducted in Part 4 of Phase I; and (d) Passing of Ph.D. general examinations. The training in Phase II will consist of the execution of a population- based etiologic case control study investigating the genetic component of early onset periodontitis. The specific research hypothesis of the studies are: H01: There is no association between HLA tissue types and early-onset periodontitis. H02: HLA haplotypes and the "early-onset periodontitis" gene segregate independently. Rejection of these hypotheses would lead to a significant improvement of our understanding of the genetic component of early onset periodontitis and lead to several potential clinical applications: (1) diagnosis, (2) identification of high risk individuals, (3) preventive treatment programs, and (4) classification of periodontal diseases. In summary, the proposed training program will provide Dr. Hujoel with a sound training in the design, analyses, and execution of clinical trials. It will provide him with the opportunity to develop into an independent research investigator, to obtain research experience under the supervision of the Department of Epidemiology and Biostatistics, and to initiate a research program leading to a Ph.D. Dissertation.